The present invention relates to a probe device for testing the electric characteristic of a display panel having a number of test pads arranged on a substrate, and a method of positioning probes.
Today, display panels of various sizes and configurations, including a rectangular and a square configuration, are available and extensively used with a broad range of television (TV) receivers. A display panel has electrode terminals arranged in a vertical array and a horizontal array therein. It has been customary to test a display panel with a probe head having probes corresponding in number to the electrode terminals of the display panel. For a test, after the probes have been brought into contact with the electrode terminals, signals are interchanged between the probe head and a tester body. However, this kind of scheme has the following problem unsolved. As for a large size TV receiver having a broad screen and numerous pixels, it is necessary to prepare a probe head having numerous probes equal in number to the electrode terminals of a display panel, and to repeat a test by separating the electrode terminals and probes into a plurality of groups. The test, therefore, needs a substantial period of time to complete.
Japanese Patent Laid-Open Publication No. 4-134482 discloses probes for a display panel capable of reducing the testing time. The probes taught in this document are implemented by thin wires arranged at the same pitch as the electrodes of a display panel or by a tab substrate. A plurality of probe assemblies each having such probes are combined horizontally and vertically and integrally mounted to a frame. For the measurement of the electric characteristic of a display panel, the probes are brought into contact with all of the electrode terminals of the display panel at the same time.
The above probe assemblies each is provided with a respective manipulator for adjusting the positions of the ends of the probes. With the manipulators, it is possible to reduce the number of probe assemblies to be combined for the number of electrode terminals increasing with an increase in the size of a display panel. Specifically, each manipulator is capable aligning the probes of the associated probe assembly with the electrode terminals of a display panel.
However, it is difficult for the conventional probe assemblies to deal with display panels each having electrode terminals arranged at a particular pitch. Specifically, every time the pitch of the electrode terminals changes, the probe assemblies must be replaced and adjusted. That is, various probe assembly units each assigned to a particular pitch must be prepared, increasing the operation cost. Further, if the probes of the individual probe assembly unit are aligned with the electrode terminals by eye, then a prohibitive number of adjusting steps are necessary, depending on the person. Moreover, whether or not the probes and electrode terminals are accurately aligned can be determined only after the start of measurement.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 1-121778, 2-90, and 3-218472.